Materials for polishing liquid for metal, polishing liquid for metal, method for preparation thereof and polishing method using the same

ABSTRACT

Provided are a metal-polishing liquid that comprises an oxidizing agent, an oxidized-metal etchant, a protective film-forming agent, a dissolution promoter for the protective film-forming agent, and water; a method for producing it; and a polishing method of using it. Also provided are materials for the metal-polishing liquid, which include an oxidized-metal etchant, a protective film-forming agent, and a dissolution promoter for the protective film-forming agent.

This application is a Divisional application of application Ser. No.09/869,347, filed Sep. 7, 2001, the contents of which are incorporatedherein by reference in their entirety. No. 09/869,347 is a NationalStage Application of international (PCT) Application No. PCT/JP99/07402,filed Dec. 28, 1999.

TECHNICAL FIELD

The present invention relates to a metal-polishing liquid especiallyfavorable for steps of wiring semiconductor devices, and to a polishingmethod of using the metal-polishing liquid.

BACKGROUND ART

Various new microfabrication techniques have been being developed tosatisfy the recent requirements of increased integration and advancedperformance of large-scale integrated circuits (hereinafter referred toas LSI) of semiconductor devices. Chemical mechanical polishing(hereinafter referred to as CMP) is one of them, and this is frequentlyutilized in LSI production, especially for insulating interlayerplanarization, metal plug formation, buried wiring pattern formation andthe like in multi-level interconnection, for LSI production. Thistechnique is disclosed, for example, in U.S. Pat. No. 4,944,836.

Recently, copper alloys have been being tried for interconnection torealize high-performance LSI. However, copper alloys are difficult touse in a process of dry-etching microfabrication that is frequently usedin interconnection with conventional aluminum alloys. For this reason, adamascene process is essentially employed for microfabrication with suchcopper alloys, which comprises depositing a thin film of a copper alloyon an insulating film having grooves previously formed therein, tothereby bury the copper alloy in the grooves, and thereafter removingthe thin copper alloy film not buried in the grooves through CMP to forma buried wiring pattern of the copper alloy. This technique isdisclosed, for example, in Japanese Patent Laid-Open No. 2-278822.

One general method of CMP of metal comprises sticking a polishing pad ona circular platen, soaking it in a metal-polishing liquid, setting asubstrate having a metal film formed thereon to the polishing pad tokeep the metal film in contact with the pad, and rotating the platenwhile a predetermined pressure (this is hereinafter referred to as apolishing pressure) is applied to its back to thereby remove the excessmetal film owing to the mechanical friction between the polishing liquidand the hilled area of the metal film.

The metal-polishing liquid for CMP generally comprises an oxidizingagent and solid abrasive grains, optionally containing an oxidized-metaletchant and a protective film-forming agent. It is considered that thebasic mechanism of CMP comprises oxidizing the surface of a metal filmfollowed by scraping away the oxidized layer from the metal film by theaction of solid abrasive grains. In the process of CMP, the oxidizedlayer of the metal surface in the grooved area of the metal film is notalmost brought into contact with the polishing pad and is thereforealmost free from the scraping action of the solid abrasive grains.Accordingly in this, the metal layer in the hilled area is removedthrough CMP, and the surface of the substrate is thereby planarized. Thedetails of the process are disclosed in Journal of ElectrochemicalSociety, Vol. 138, No. 11 (issued in 1991), pp. 3460-3464.

It is generally said that an oxidized-metal etchant, if added to themetal-polishing liquid, is effective for increasing the polishing ratein CMP. For the reason, it is understood that the oxidized-metal etchantadded dissolves the metal oxide particles having been scraped off by thesolid abrasive grains in the metal-polishing liquid to thereby enhancethe scraping ability of the solid abrasive grains. The metal-oxideetchant added increases the polishing rate in CMP, while, on the otherhand, it etches even the oxidized layer of the metal film surface in thegrooved area, As a result, the metal film surface in that area isexposed, and it is then further oxidized with the oxidizing agent. Afterthis is repeated, the metal film in the grooved area is thereby muchetched. Accordingly, in a case where such an oxidized metal etchant isadded to a metal-polishing liquid, the center part of the surface isdepressed like a dish (this phenomenon is hereinafter referred to asdishing) and therefore could not be well planarized. To avoid this, aprotective film-forming agent may be added to the metal-polishingliquid. In the metal-polishing liquid containing such a protectivefilm-forming agent, it is important to well balance the effect of theoxidized-metal etchant with that of the protective film-forming agent inorder that the etchant does not so much etch the oxidized layer of ametal film surface in the grooved area thereof but can efficientlydissolve the scraped oxidized layer particles so as to increase thepolishing rate in CMP.

Adding such an oxidized-metal etchant and a protective film-formingagent to a metal-polishing liquid to expect their chemical reactionsincreases the CMP rate (that is, the polishing rate in CMP) and iseffective for reducing the damage of the metal layer surface polishedthrough CMP.

However, the following problems (1) to (4) are inevitable in the processof buried wiring pattern formation through CMP with a conventionalmetal-polishing liquid that contains solid abrasive grains.

(1) The center part of the surface of the buried metal wiring pattern isisotropically etched (dishing).

(2) The surface polished with the liquid is scratched by the solidabrasive grains.

(3) After polished, the surface must be washed to remove the solidabrasive grains still remaining thereon, but the washing operation istroublesome.

(4) The solid abrasive grains are expensive, and the waste treatment iscostly. Accordingly, the cost of the CMP process itself is high.

In addition, most of the metal-polishing liquid is water. Therefore, thetank for transporting the liquid therein must be large, and the tank forstoring it in a polishing plant must be also large. That is, themetal-polishing liquid requires a large space for producing, storing,transporting and using it, and this is a bar to automation in using theliquid in a polishing plant. Moreover, the cost of recycling the tanksused for transporting the liquid is extremely high, and this is stillanother problem.

The problems may be solved if a concentrate of the metal-polishingliquid not containing a large amount of solid abrasive grains can beprepared. The production costs in metal-polishing liquid makers could bereduced, and, as a result, the costs of the dilutions of the concentratecould also be reduced. In addition, mass-production of the concentratedoes not require increasing the scale of the existing production plants,for which, therefore, no additional capital investment is needed. Thisis another advantage of the concentrate. In view of the advantages inusing it, the concentrate is preferably prepared to have a degree ofconcentration of at least 10 times that of the diluted liquid thereof tobe actually used in metal polishing.

On the other hand, for LSI interconnection of high reliability withneither dishing nor copper alloy etching in the polishing process,proposed is a method of using a metal-polishing liquid that comprisesaminoacetic acid e.g., glycine or amidosulfuric acid serving as anoxidized-metal etchant, and benzotriazole (hereinafter referred to asBTA) serving as a protective film-forming agent. This technique isdescribed, for example, in Japanese Patent Laid-Open No. 8-83780.

However, since the solubility in water of BTA is low (2 g in 100 cc of20° C. water), some metal-polishing liquids of that type could not beconcentrated into 10-fold concentrates (for example, the metal-polishingliquid containing 0.2% by weight of BTA can be concentrated into 5-foldconcentrates, but if concentrated into 10-fold concentrates, BTA isdeposited therein at 0° C. or lower). Accordingly, desired is ametal-polishing liquid containing BTA and capable of being concentratedinto 10-fold or more concentrates, not forming a deposit of BTA in theconcentrates even in ordinary environments at 0° C. or higher.

DISCLOSURE OF THE INVENTION

One object of the present invention is to provide a metal-polishingliquid capable of being readily prepared by diluting a metal-polishingliquid material of high concentration and capable of realizing theformation of buried metal film patterns of high reliability. Anotherobject of the invention is to provide a method for producing themetal-polishing liquid; a metal-polishing liquid material to be used inthe method; and a polishing method of using the polishing liquid.

To attain the objects as above, the invention provides a metal-polishingliquid that comprises an oxidizing agent, an oxidized-metal etchant, aprotective film-forming agent, a dissolution promoter for the protectivefilm-forming agent, and water.

The metal-polishing liquid of the invention may contain abrasive grains,but may not substantially contain solid abrasive grains. In the casewhere it contains solid abrasive grains, it is possible to performhigh-speed polishing. In the case where it does not contain solidabrasive grains, abrasive scratches are drastically reduced since CMPwithout solid abrasive grains is attained by friction to a polishing padthat is mechanically far softer than solid abrasive grains.

As a material for preparing the metal-polishing liquid of the invention,herein provided is a metal-polishing liquid material that comprises anoxidized-metal etchant, a protective film-forming agent and adissolution promoter for the protective film-forming agent. Themetal-polishing liquid material of the invention may further contain anoxidizing agent, water and/or abrasive grains.

It is easy to prepare a metal-polishing liquid from the metal-polishingliquid material of the invention by diluting the material and optionallyadding thereto any additional ingredients, For this, the inventionprovides a method for producing a metal-polishing liquid that comprisesa step of diluting the metal-polishing liquid material of the inventionwith a diluent,

For the diluent, preferred is water or an aqueous diluent solution. Theaqueous diluent solution preferably contains at least one of anoxidizing agent, an oxidized-metal etchant, a protective film-formingagent and a dissolution promoter for the protective film-forming agent,The above-mentioned dilution step in the method may be for diluting themetal-polishing liquid material that contains at least one ingredient ofan ingredient group consisting of an oxidizing agent, an oxidized-metaletchant, a protective film-forming agent and a dissolution promoter forthe protective film-forming agent, with an aqueous diluent solution ofat least one ingredient of the ingredient group.

The metal-polishing liquid material of the invention may be acomposition prepared by mixing all the constituent ingredients, or maybe a combination of at least two compositions each containing any of theconstituent ingredients. Concretely, for example, the metal-polishingliquid material of the invention may be composed of a first constituentelement and a second constituent element not mixed as yet. In this, thefirst constituent element contains at least one ingredient of aningredient group consisting of an oxidizing agent, an oxidized-metaletchant, a protective film-forming agent and a dissolution promoter forthe protective film-forming agent; and the second constituent elementcontains the other ingredients of the ingredient group.

For preparing a metal-polishing liquid from the metal-polishing liquidmaterial that comprises at least two constituent elements as above, theinvention herein provides a method that comprises a step of mixing theabove-mentioned first and second constituent elements and a diluent inany desired order. The order of mixing them is not specifically defined,and may be determined in any desired manner, depending on the propertiesof the compounds to be used and the temperature of the liquids to bemixed.

Preferably, the first constituent element contains an oxidizing agent,and the second constituent element contains an oxidized-metal etchant, aprotective film-forming agent, and a dissolution promoter for theprotective film-forming agent. If desired, the first constituent elementmay contain a protective film-forming agent and a dissolution promoterfor the agent. Also if desired, the first and second constituentelements may independently contain any other ingredients.

It is desirable that the oxidizing agent is not heated at a temperaturehigher than 40° C., since the decomposition of the agent is promoted atsuch a high temperature. Therefore, in the mixing step, it is desirablethat the oxidizing agent and a mixture containing it (for example, thefirst constituent element, as well a mixture of the first and secondconstituent elements, and also their dilutions) are kept at atemperature at highest 40° C.

Preferably, at least a part of the protective film-forming agent is inthe form of solid particles having a mean particle size of at most 100μm, and the agent of this type is dissolved or dispersed in themetal-polishing liquid. Unless otherwise specifically indicated, themean particle size referred to herein indicates a number-averageparticle size of particles.

The invention further provides a polishing method using themetal-polishing liquid of the invention. Specifically, the polishingmethod which the invention provides comprises applying themetal-polishing liquid of the invention to a polishing pad set on aplaten, and while keeping the surface of an article to be polished incontact with the polishing pad, moving the polishing pad and the surfaceof the article relatively to each other to thereby polish the surface ofthe article.

The polishing method of the invention may further comprises a step ofmixing the first and second constituent elements and a diluent in anydesired order to prepare the metal-polishing liquid, prior to thepolishing step.

Different from conventional polishing liquids, the metal-polishingliquid of the invention is readily prepared from the metal-polishingliquid material having a high concentration by diluting the material,and therefore its advantages are that the costs for producing themetal-polishing liquid can be reduced, the capacity of the tanks fortransporting the liquid can be reduced, and the capacity of the tanksfor storing, transporting and using it in polishing plants can bereduced.

To the metal polishing liquid, added is a dissolution promoter which isfor essentially increasing the solubility in water of the protectivefilm-forming agent. Accordingly, the material for the metal-polishingliquid may have a broader and higher concentration, in accordance withthe polishing capabilities of the liquid.

A. Constituent Ingredients:

The constituent ingredients of the metal-polishing liquid material andthe metal-polishing liquid of the invention are described hereinunder.

(1) Dissolution Promoter;

The dissolution promoter for use in the invention is preferably asolvent in which the solubility of the protective film-forming agent isat least 25 g/liter, or a surfactant. These may be used either singly oras combined.

a. Surfactant:

A surfactant, if added to the metal-polishing liquid material or themetal-polishing liquid of the invention, increases the solubility inwater of the protective film-forming agent, since the hydrophobic groupsin the protective film-forming agent adsorb the surfactant and thehydrophilic groups in the thus-adsorbed surfactant act to increase themiscibility of the agent with water.

The surfactant includes, for example, esters, ethers, polysaccharides,salts of amino acids, polycarboxylic acids, salts of polycarboxylicacids, vinyl polymers, sulfonic acids, salts of sulfonic acids, andamides. One or more of these may be used either singly or as combined.

The surfactant is grouped into anionic surfactants, cationicsurfactants, ampholytic surfactants and nonionic surfactants. Preferredexamples of the surfactants of all those groups for use herein arementioned below.

The anionic surfactants include salts of carboxylic acids, salts ofsulfonic acids, salts of sulfate esters, and salts of phosphoric esters.

The salts of carboxylic acids include soap, salts of N-acylamino acids,polyoxyethylene alkyl ether-carboxylates, polyoxypropylene alkylether-carboxylates, acylated peptides, etc.

The salts of sulfonic acids include alkylsulfonates,alkylbenzenesulfonates, alkynaphthalenesulfonates,naphthalenesulfonates, sulfosuccinates, α-olefin-sulfonates,N-acylsulfonates, etc.

The salts of sulfate esters include sulfated oils, salts ofalkylsulfates, salts of alkylether-sulfates, salts of polyoxyethyleneallyl ether-sulfates, salts of polyoxypropylene alkylallylether-sulfates, salts of alkylamidosulfates, etc.

The salts of phosphoric esters include salts of alkylphosphates, saltsof polyoxyethylene alkylallyl ether phosphates, salts ofpolyoxypropylene alkylallyl ether phosphates, etc.

The cationic surfactants Include aliphatic amine salts, aliphaticquaternary ammonium salts, chlorobenzalkonium salts chlorobenzetonium,pyridinium salts, imidazolinium salts, etc.

The ampholytic surfactants include carboxybetaine-type surfactants,salts of aminocarboxylic acids, imidazolinium betaine, lecithin,alkylamine oxides, etc.

The nonionic surfactants include ether-type, ether-ester-type,ester-type, and nitrogen-containing surfactants, etc.Fluorine-containing surfactants are also preferred for use herein.

The ether-type surfactants include polyoxyethylene alkyl ethers,polyoxyethylene alkylphenyl ethers, alkylallylformaldehyde-condensedpolyoxyethylene ethers, polyoxyethylene-polyoxypropylene block polymers,polyoxyethylene-polyoxypropylene alkyl ethers, etc.

The ether-ester-type surfactants include glycerin ester-polyoxyethyleneethers, sorbitan ester-polyoxyethylene ethers, sorbitolester-polyoxyethylene ethers, etc.

The ester-type surfactants include polyethylene glycol-fatty acidesters, glycerin esters, polyglycerin esters, sorbitan esters, propyleneglycol esters, sucrose esters, etc.

The nitrogen-containing surfactants include fatty acid alkanolamides,polyoxyethylene-fatty acid amides, polyoxyethylene-alkylamides, etc.

In addition, the following surfactants are also preferred for useherein:

esters such as glycerin esters, sorbitan esters, methoxyacetate,ethoxyacetate and 3-ethoxypropionate, alanine ethyl ester, etc.;

ethers such as polyethylene glycols, polypropylene glycols,polytetramethylene glycols, polyethylene glycol alkyl ethers,polyethylene glycol alkenyl ethers, alkylpolyethylene glycols,alkylpolyethylene glycol alkyl ethers, alkylpolyethylene glycol alkenylethers, alkenylpolyethylene glycols, alkenylpolyethylene glycol alkylethers, alkenylpolyethylene glycol alkenyl ethers, polypropylene glycolalkyl ethers, polypropylene glycol alkenyl ethers, alkylpolypropyleneglycols, alkylpolypropylene glycol alkyl ethers, alkylpolypropyleneglycol alkenyl ethers, alkenylpolypropylene glycols,alkenylpolypropylene glycol alkyl ethers, alkenylpolypropylene glycolalkenyl ethers, etc.;

sulfonic acids such as methyltauric acid, methyl sulfate, butyl sulfate,vinylsulfonic acid, 1-allylsulfonic acid, 2-allylsulfonic acid,methoxymethylsulfonic acid, ethoxymethylsulfonic acid,3-ethoxypropylsulfonic acid, etc.;

salts of sulfonic acids such as ammonium methyltaurate, sodiummethyltaurate, sodium methylsulfate, ammonium ethylsulfate, ammoniumbutylsulfate, sodium vinylsulfonate, sodium 1-allylsulfonate, sodium2-allylsulfonate, sodium methoxymethylsulfonate, ammoniumethoxymethylsulfonate, sodium 3-ethoxypropylsulfonate, sodiumsulfosuccinate, etc.; and

amides such as propionamide, acrylamide, methylurea, nicotinamide,succinamide, sulfanylamide, etc.

In a case where articles to be polished by the polishing liquid of theinvention are silicon substrates for LSI, it is undesirable tocontaminate them with alkali metals, alkaline earth metals and halides,therefore, acids or their ammonium salts are preferred. However, in acase where articles to be polished are glass substrates and the like, nolimitation is needed for them.

The amount of the surfactant in the metal-polishing liquid (this isready for use, prepared from a material for it by optionally adding anydesired additives thereto and by diluting it with a diluent) preferablyfalls between 0.01 g and 3 g relative to 100 g of the total of theoxidizing agent, the oxidized-metal etchant, the protective film-formingagent, the surfactant and water. More preferably, it fails between 0.03g and 1 g, particularly preferably between 0.1 g and 0.8 g. If itsamount is smaller than 0.01 g, the surfactant added will be ineffective;but if larger than 3 g,

too much surfactant will lower the rate of CMP.

b. Solvent:

To the polishing liquid material of the invention, added is a solvent inwhich the solubility of the protective film-forming agent existing inthe material is at least 25 g/liter in order to increase the solubilityin water of the protective film-forming agent. Preferably, thesolubility in the solvent of the protective film-forming agent is atleast 40 g/liter, more preferably at least 50 g/liter. To that effect,especially preferred are good solvents for the protective film-formingagent.

Preferred examples of the solvent serving as the dissolution promoterfor the protective film-forming agent in the invention are organicsolvents such as alcohols, ethers, ketones, etc. These solvents may beused either singly or as a combination of any two kinds thereof or more.

Preferred solvents for the dissolution promoter for use in the inventionare mentioned below.

Alcohols such as methanol, ethanol, 1-propanol, 2-propanol,2-propyn-1-ol, allyl alcohol, ethylene cyanohydrin, 1-butanol,2-butanol, (S)-(+)-2-butanol, 2-methyl-1-propanol, t-butyl alcohol,perfluoro-t-butyl alcohol, t-pentyl alcohol, 1,2-ethanediol,1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 2,3-butanediol,1,5-pentanediol, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin,2-ethyl-2-(hydroxymethyl)-1,3-propanediol, 1,2,6-hexanetriol, etc.;

Ethers such as dioxane, trioxan, tetrahydrofuran, diethylene glycoldiethyl ether, 2-methoxyethanol, 2-ethoxyethanol,2,2-(dimethoxy)ethanol, 2-isopropoxyethanol, 2-butoxyethanol,1-methoxy-2-propanol, 1-ethoxy-2-propanol, furfuryl alcohol,tetrahydrofurfuryl alcohol, ethylene glycol, diethylene glycol,diethylene glycol monomethyl ether, diethylene glycol monoethyl ether,diethylene glycol monobutyl ether, triethylene glycol, triethyleneglycol monomethyl ether, tetraethylene glycol, dipropylene glycol,dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether,tripropylene glycol monomethyl ether, diacetone alcohol, 2-methoxyethylacetate, 2-ethoxyethyl acetate, diethylene glycol monoethyl etheracetate, etc.;

Ketones such as acetone, methyl ethyl ketone, acetylacetone,cyclohexanone, etc.

Of those solvents, more preferred are methanol, ethanol, 2-propanol,tetrahydrofuran, ethylene glycol, acetone, and methyl ethyl ketone.

The amount of the solvent added to the polishing liquid material is notspecifically defined, but is preferably smaller than 50 g relative to100 g of the total amount of the material. More preferably, it issmaller than 25 g. If the amount of the solvent is 50 g or more, thereis the possibility that the rate of CMP is lowered because the interfaceto be polished is in a state different from that in the case of awater-based solvent system.

(2) Protective Film-Forming Agent:

The protective film-forming agent is to form a protective film on thesurface of the metal. It includes, for example, nitrogen-containingcompounds such as ammonia, alkylamines, amino acids, imines and azoles,and their salts; sulfur-containing compounds such as mercaptans; andwater-soluble polymers such as polysaccharides, polycarboxylic acids,salts of polycarboxylic acids, vinyl polymers, etc. These may be usedeither singly or as a combination of two kinds thereof or more.

Preferred examples of the protective film-forming agent for use in theinvention are mentioned below:

ammonia;

amines, for example, alkylamines such as dimethylamine, trimethylamine,triethylamine, propylenediamine, etc.; ethylenediaminetetraacetic acid(EDTA), sodium diethyldithiocarbamate, chitosan, etc.;

amino acids such as glycine, L-alanine, β-alanine, L-2-aminobutyricacid, L-norvaline, L-valine, L-leucine, L-norleucine, L-isoleucine,L-alloisoleucine, L-phenylalanine, L-proline, sarcosine, L-ornithine,L-lysine, taurine, L-serine, L-threonine, L-allothreonine, L-homoserine,L-tyrosine, 3,5-diiodo-L-tyrosine, β-(3,4-dihydroxyphenyl)-L-alanine,L-thyroxine, 4-hydroxy-L-proline, L-cysteine, L-methionine, L-ethionine,L-lanthionine, L-cystathionine, L-cystine, L-cysteic acid, L-asparticacid, L-glutamic acid, S-(carboxyrmethyl)-L-cysteine, 4-aminobutyricacid, L-asparagine, L-glutamine, azaserine, L-arginine, L-canavanine,L-citrulline, δ-hydroxy-L-lysine, creatine, L-kynurenine, L-histidine,1-methyl-L-histidine, 3-methyl-L-histidine, ergothioneine, L-tryptophan,actinomycin C1, apamine, angiotensin I, angiotensin II, antipine, etc.;

imines such as dithizone, cuproin (2,2′-biquinoline), neocuproin(2,9-dimethyl-1,10-phenanthroline), vasocuproin(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), cuperazone(biscyclohexanone-oxalylhydrazone), etc.;

azoles such as benzimidazole-2-thiol,2-[2-(benzothiazolyl)]thiopropionic acid,2-[2-(benzothiazolyl)]thiobutyric acid; 2-mercaptobenzothiazole,1,2,3-triazole, 1,2,4-triazole, 3-amino-1H-1,2,4-triazole,benzotriazole, 1-hydroxybenzotriazole, 1-dihydroxypropylbenzotriazole,2,3-dicarboxypropylbenzotriazole, 4-hydroxybenzotriazole,4-carboxyl-1H-benzotriazole, 4-methoxycarbonyl-1H-benzotriazole,4-butoxycarbonyl-1H-benzotriazole, 4-octyloxycarbonyl-1H-benzotriazole,5-hexylbenzotriazole,N-(1,2,3-benzotriazolyl-1-methyl)-N-(1,2,4-triazolyl-1-methyl)-2-ethylhexylamine, tolyltriazole, naphthotriazole, bis[(1-benzotriazolyl)methyl]phosphonic acid, etc.;

mercaptans such as nonylmercaptan, dodecylmercaptan, triazinethiol,triazinedithiol, triazinetrithiol, etc.;

polysaccharides such as alginic acid, pectic acid, carboxymethylcellulose, curdlane, pullulane, etc.;

salts of amino acids such as glycine ammonium salt, glycine sodium salt,etc.;

polycarboxylic acids and their salts, such as polyaspartic acid,polyglutamic acid, polylysine, polymalic acid, polymethacrylic acid,ammonium polymethacrylate, sodium polymethacrylate, polyamidic acid,polymaleic acid, polyitaconic acid, polyfumaric acid,poly(p-styrenecarboxylic acid), polyacrylic acid, polyacrylamide,aminopolyacrylamide, ammonium polyacrylate, sodium polyacrylate,ammonium polyamidate, sodium polyamidate, polyglyoxylic acid, etc.; and

vinyl polymers such as polyvinyl alcohol, polyvinylpyrrolidone,polyacrolein, etc.

Of those protective film-forming agents, preferred are chitosan,ethylenediaminetetraacetic acid, L-tryptophan, cuperazone,triazinedithiol, benzotriazole, 4-hydroxybenzotriazole,4-carboxy-1H-benzotriazole butyl ester, tolyltriazole, naphthotriazole,polymalic acid, polyacrylic acid, polyacrylamide, ammonium polyacrylate,and polyvinyl alcohol, as they satisfy the two requirements of high CMPrate and low etching rate.

The amount of the protective film-forming agent to be added to themetal-polishing liquid preferably falls between 0.0001 mol and 0.05 mol,more preferably between 0.0003 mol and 0.005 mol, particularlypreferably between 0.0005 mol and 0.0035 mol, relative to 100 g of thetotal amount of the oxidizing agent, the oxidized-metal etchant, theprotective film-forming agent, the dissolution promoter and water thatconstitute the liquid. If its amount is smaller than 0.0001 mol, theprotective film-forming agent will be ineffective for etchingretardation; but if larger than 0.05 mol, the rate of CMP will belowered.

Preferably, the amount of the protective film-forming agent, of whichthe solubility in water at room temperature is lower than 5% by weight,to be used in preparing the metal-polishing liquid material is notlarger than 2 times the solubility of the agent in water at roomtemperature, more preferably not larger than 1.5 times. Concretely, ingeneral, the amount of the protective film-forming agent preferablyfalls between 0.0001 mol and 0.05 mol, preferably between 0.0003 mol and0.05 mol, more preferably between 0.0005 mol and 0.0035 mol, relative to100 g of the metal-polishing liquid material. If the amount of theprotective film-forming agent therein is larger than 2 times thesolubility in water of the agent, the concentrated liquid material couldnot be prevented from forming a deposit of the agent when cooled at 5°C.

In a case where the protective film-forming agent to be used inpreparing the metal-polishing liquid material of the invention is solid,it is desirable that the solid agent has a mean particle size of at most100 μm and is dissolved or dispersed in the metal-polishing liquidmaterial. Concretely, when the liquid material is composed of at leasttwo constituent elements not mixed as yet (each element may be a singlesubstance or a composition of substances), the solid agent may bedissolved or dispersed in at least one constituent element. The solid,protective film-forming agent having such a small particle size can beprepared, for example, by grinding the solid agent. Using the solid,protective film-forming agent having such a small particle size isdesirable, as the surface area of the agent is large and therefore thedissolution rate of the agent is high. In addition, even if fineparticles of the solid agent are dispersed in the liquid material, notdissolved therein, they may be readily dissolved therein within a shortperiod of time when they are mixed with the other ingredients and/or adiluent. Therefore, the mean particle size of the solid agent ispreferably at most 50 μm, more preferably at most 20 μm.

(3) Oxidizing Agent:

The oxidizing agent to be used in the invention is a compound capable ofoxidizing metals. Preferred examples of the oxidizing agent for useherein are hydrogen peroxide, nitric acid, potassium periodate,hypochlorous acid, ozonized water, etc. Of those oxidizing agents,especially preferred is hydrogen peroxide (H₂O₂). In case where thearticles to be polished are silicon substrates with semiconductor chipsmounted thereon, it is undesirable to contaminate the articles withalkali metals, alkaline earth metals and halides, therefore, preferredare oxidizing agents not containing a non-volatile component. However,since ozonized water is unstable due to its greatly varying with time,most preferred is hydrogen peroxide. In a case where articles to bepolished are glass substrates with no semiconductor chips thereon, theoxidizing agent may contain a non-volatile component.

The amount of the oxidizing agent to be in the metal-polishing liquid ofthe invention preferably falls between 0.003 mol and 0.7 mol, morepreferably between 0.03 mol and 0.5 mol, particularly preferably between0.2 mol and 0.3 mol, relative to 100 g of the total amount of theoxidizing agent, the oxidized-metal etchant, the protective film-formingagent, the dissolution promoter and water. If the amount of theoxidizing agent is smaller than 0.003 mol, metal oxidation with it willbe unsatisfactory and the rate of CMP will be lowered; but if largerthan 0.7 mol, too much oxidizing agent will roughen the surface of thearticle. The amount of the oxidizing agent to be in the metal-polishingliquid material generally falls between 0.03 and 0.7 mol relative to 100g of the material, but preferably falls between 0.3 mol and 0.5 mol,more preferably between 0.2 mol and 0.3 mol relative to 100 g of thematerial.

(4) Oxidized-Metal Etchant:

For the oxidized-metal etchant, preferred is a water-soluble compound.Its preferred examples are organic acids, sulfuric acid and theirammonium salts. These compounds may be used either singly or as acombination of two kinds thereof or more. When used in preparing thepolishing liquid or the polishing liquid material, the compound may beadded in the form of its aqueous solution.

Specific examples of the oxidized-metal etchant are mentioned below:

organic acids such as formic acid, acetic acid, propionic acid, butyricacid, valeric acid, 2-methylbutyric acid, n-hexanoic acid,3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid,n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid,2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid,glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid,adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid,tartaric acid, citric acid, etc.;

inorganic acids such as sulfuric acid, nitric acid, chromic acid, etc.;

ammonia; and

salts such as ammonium salts of the above-mentioned organic or inorganicacids (e.g., ammonium persulfate, ammonium nitrate, ammonium chloride),etc.

These may be used either singly or as a combination of two kinds thereofor more.

Of the compounds, formic acid, malonic acid, malic acid, tartaric acidand citric acid are favorable to films of copper, copper alloys, copperoxides or copper alloy oxides (and also to laminate films containing atleast one of these metal layers). In particular, malic acid, tartaricacid and citric acid are preferred, as they ensure a practicable rate ofCMP and can effectively control the etching rate.

The amount of the oxidized-metal etchant to be in the metal-polishingliquid of the invention preferably falls between 0.000001 mol and 0.005mol, more preferably between 0.00005 mol and 0.0025 mol, particularlypreferably between 0.0005 mol and 0.0015 mol, per 100 g of the totalamount of the oxidizing agent, the oxidized-metal etchant, theprotective film-forming agent, the dissolution promoter and water. Ifthe amount of the etchant is larger than 0.005 mol, control of theetching tends to be difficult. The amount of the oxidized-metal etchantto be in the metal-polishing liquid material of the invention may fallgenerally between 1×10⁻⁶ mol and 0.005 mol, but preferably between5×10⁻⁵ mol and 0.0025 mol, more preferably between 0.0005 mol and 0.0015mol, relative to 100 g of the metal-polishing liquid material,

(5) Abrasive Grains:

The metal-polishing liquid of the invention may not substantiallycontain solid abrasive grains, but may contain them.

In a case where abrasive grains are used, the order of mixing and alsothe ingredients with which the abrasive grains are mixed are notspecifically defined, When the metal-polishing liquid material iscomposed of at least two constituent elements not mixed as yet (eachelement may be a single substance or a composition of substances),abrasive grains may be in any constituent element (that may be a singlesubstance or a composition of substances), or may be in two or more suchconstituent elements.

The abrasive grains may be any of, for example;

inorganic abrasive grains of silica, alumina, ceria, titania, zirconia,germania, silicon carbide, etc.; and

organic abrasive grains of polystyrene, polyacrylates, polyvinylchloride, etc.

Preferred for use herein are colloidal silica and colloidal aluminahaving a mean particle size of at most 100 nm, since their dispersionstability in the polishing liquid is good and since they form fewscratches in CMP with the liquid. More preferably, the mean particlesize of the abrasive grains is at most 20 nm, since such small abrasivegrains are effective for more rapidly polishing barrier layers, and forpolishing silicon dioxide at a lower rate.

For colloidal silica, known is a method of producing it throughhydrolysis of silicon alkoxides or through ion-exchange of sodiumsilicate. For colloidal alumina, also known is a method of producing itthrough hydrolysis of aluminium nitrate.

The amount of the abrasive grains to be in the metal-polishing liquid(this is ready for use, prepared from a material for it by optionallyadding any desired additives thereto and by diluting it with a diluent)preferably falls between 0.01 and 10% by weight of the total amount ofthe liquid, more preferably between 0.05 and 5% by weight thereof. Iftheir amount is smaller than 0.01% by weight, the abrasive grains addedwill be ineffective; but even if larger than 10% by weight, the rate ofCMP will be saturated and will be no more increased. The amount of theabrasive grains to be in the metal-polishing liquid material of theinvention preferably falls between 0.01 and 10% by weight, morepreferably between 0.05 and 5% by weight of the total amount of thepolishing liquid material.

(6) Water:

The metal-polishing liquid material of the invention may contain water.The amount of water in the material may be suitably determined,depending on the other constituent ingredients and their solubility inwater. In general, the water content of the material may fall between 50and 98% by weight, preferably between 70 and 90% by weight. In a casewhere some constituent ingredients of the material contain water, forexample, when the oxidizing agent in the material is aqueous hydrogenperoxide, the amount of water to be in the metal-polishing liquidmaterial that contains such a water-containing ingredient is morepreferably from 75 to 85% by weight. On the other hand, the amount ofwater to be in the metal-polishing liquid material not containing such awater-containing ingredient is more preferably from 80 to 90% by weight.

B. Method of Producing Metal-Polishing Liquid:

The metal-polishing liquid of the invention is prepared by diluting themetal-polishing liquid material of the invention, with a diluent. Theconcentration of each constituent ingredient in the metal-polishingliquid material (that is, the compositional ratio) shall be determined,depending on the composition and the amount of the diluent to be usedfor diluting the material and on the concentration of each constituentingredient of the metal-polishing liquid to be prepared (that is, thecompositional ratio).

In a case where water is used for the diluent, the metal-polishingliquid material is so prepared that its composition and compositionalratio of the constituent ingredients except water are the same as thoseof the metal-polishing liquid; or that is, the water content of thematerial is reduced to have an increased concentration. In thatcondition, when water is added to the material to dilute it, then ametal-polishing liquid having a desired composition can be prepared.

On the other hand, in a case where an aqueous solution is used for thediluent, it is preferred that an aqueous solution containing at leastone of an oxidizing agent, an oxidized-metal etchant, a protectivefilm-forming agent and a dissolution promoter for the protectivefilm-forming agent is used. In this case, a metal-polishing liquidmaterial that contains at least one ingredient of the group consistingof an oxidizing agent, an oxidized-metal etchant, a protectivefilm-forming agent and a dissolution promoter for the protectivefilm-forming agent is diluted with an aqueous diluent solution of atleast one ingredient of that ingredient group to prepare themetal-polishing liquid of the invention. To this, any other desiredingredients may be added at the dilution.

In that case of using such an aqueous diluent solution, theconcentration of each ingredient of the metal-polishing liquid materialshall be so determined that the material can form, after themetal-polishing liquid material and the aqueous diluent solution (andadditives to be added as required) have been mixed, a metal-polishingliquid having a desired composition and a desired concentration.Accordingly in the case, hardly-soluble ingredients can be incorporatedwith the metal-polishing liquid material in a form of an aqueoussolution, and therefore the concentration of the material formetal-polishing liquid can be more increased. For that purpose, it isdesirable that the aqueous solution contains a protective film-formingagent of low solubility and a dissolution promoter for the agent.

In a case where the metal-polishing liquid material is composed of atleast two constituent elements not mixed as yet (each element may be asingle substance or a composition of substances), the order of mixingthe constituent elements with a diluent is not specifically defined, andit may be determined in any desired manner depending on the solubilityof each constituent ingredient and on the temperature at which they aredissolved. For example, one or more constituent elements are mixed witha diluent added thereto and thereafter with the other constituentelements; or the constituent elements are first mixed and then with adiluent added thereto; or a diluent is first added to and mixed witheach constituent element and thereafter the resulting constituentelements are mixed. Any of such methods may be employed for mixing theconstituent elements with a diluent.

Concretely, for example, when used is the metal-polishing liquidmaterial composed of a first constituent element A of an oxidizing agentand a second constituent element B that comprises an oxidized-metaletchant, a protective film-forming agent, a dissolution promoter andwater, any of the following methods (1) to (5) may be selected andemployed for preparing a metal-polishing liquid (or that is, fordiluting the metal-polishing liquid material).

(1) A method of mixing the constituent element A and the constituentelement B followed by diluting the resulting mixture with a diluent.

(2) A method of diluting the constituent element A with a diluentfollowed by mixing it with the constituent element B.

(3) A method of diluting the constituent element B with a diluentfollowed by mixing it with the constituent element A.

(4) A method of diluting the constituent element A and the constituentelement B separately with a diluent followed by mixing the dilutedconstituent element A and the diluted constituent element B.

(5) A method of mixing the constituent element A, the constituentelement B and a diluent almost at the same time.

An ingredient of low solubility such as a protective film-forming agentmay be divided into two or more portions to be separately in differentconstituent elements. If so, there is a case where the ingredient may bewell dissolved in each constituent element, not requiring an increasedamount of the solvent (generally, water) for it.

For example, in a case where a protective film-forming agent is dividedinto two portions to be separately in two constituent elements, themetal-polishing liquid material may be composed of a first constituentelement A that comprises an oxidizing agent, one portion of theprotective film-forming agent and a dissolution promoter, arid a secondconstituent element B that comprises an oxidized-metal etchant, theother portion of the protective film-forming agent, a dissolutionpromoter and water.

In a case where a protective film-forming agent is divided into threeportions to be separately in three constituent elements, themetal-polishing liquid material may be composed of, for example, a firstconstituent element A that comprises an oxidizing agent and a part ofthe protective film-forming agent, a second constituent element B thatcomprises an oxidized-metal etchant and another part of the protectfilm-forming agent, and a third constituent element C that comprises theremaining part of the protective film-forming agent and a dissolutionpromoter.

In such cases of dividing a metal-polishing liquid material into aplurality of constituent elements each containing a portion of one andthe same ingredient, a large amount of a protective film-forming agentof low solubility can be dissolved in a solvent (generally, water) andtherefore the concentration of the metal-polishing liquid material canbe increased. The number of the constituent elements into which theingredients of a metal-polishing liquid material are divided is notlimited to 2 or 3 as in the embodiments mentioned above, and may bedetermined in any desired manner.

The invention is not limited to the embodiments mentioned above, and mayapply to any and every method of preparing a metal-polishing liquidmaterial of high concentration that comprises a plurality of constituentelements followed by diluting the material into a desiredmetal-polishing liquid.

In the metal-polishing liquid of the invention, hydrogen peroxidesuitable for the oxidizing agent decomposes at temperatures higher than40° C. Therefore, if the liquid containing hydrogen peroxide is storedor used at temperatures higher than 40° C., the concentration of theoxidizing agent, hydrogen peroxide will vary and have some negativeinfluences on the polishing speed. Therefore, it is desirable that theoxidizing agent and a mixture containing it are kept at a temperaturenot higher than 40° C.

However, the solubility of compounds generally increases at higherliquid temperatures. Therefore, it is desirable that solutions ofcompounds of low solubility are kept at higher temperatures for ensuringhigher solubility of the compounds therein.

Accordingly in the method of producing the metal-polishing liquid of theinvention, it is desirable that the first constituent element containingan oxidizing agent is kept at a temperature not higher than 40° C. whilethe other constituent elements are kept at temperatures falling betweenroom temperature and 100° C., and that, when the first constituentelement is mixed with the other constituent elements or with a diluent,it is desired that the resulting liquid mixture is kept at a temperaturenot higher than 40° C.

In a case where a compound of low solubility is dissolved under heat,the dissolved compound will be partly deposited in the solution when thetemperature of the solution is lowered. In such a case, the solution isagain heated so as to dissolve the compound therein before use,

C. Polishing Method:

Next described is the polishing method of the invention.

The polishing method of the invention comprises polishing a metal filmwith the metal-polishing liquid of the invention to thereby remove atleast a part of the metal film. The polishing method of the invention isespecially favorable to polishing a metal laminate film containing ametal layer of at least one selected from copper, copper alloys, copperoxides and copper alloy oxides (hereinafter these are referred to simplyas copper alloys).

When the surface of a substrate, which has a desired groove patternthereon and which is coated with a metal film containing any of copperand copper alloys (copper/chromium, etc.) to fill the patterned grooveson its surface, is polished in a mode of CMP with the metal-polishingliquid of the invention, the metal film in the hilled area of thesubstrate is selectively removed through CMP while the metal film in thegrooved area thereof is left as it is, and, as a result, a desiredconductor pattern is formed on the substrate,

The present inventors have found that, when the etching rate in thepolishing step is controlled to be at most 10 nm/min, it produces a goodresult of planarization. As far as the CMP rate depression that resultsfrom the etching rate depression is within an acceptable range, theetching rate is preferably lower. For example, when the etching rate iscontrolled to be at most 5 nm/min, dishing will be negligible even in acase of about 50% excess CMP (this means that the actual working time ofCMP is about 1.5 times the time necessary for removing the intendedmetal film through CMP). Further, the etching rate, if controlled to benot higher than 1 nm/min, causes no problem of dishing even in 100% ormore excess CMP.

The etching rate referred to herein is meant to indicate the rate ofetching a metal film formed on a substrate when the substrate (this hasa grooved pattern on its surface and is coated with a metal film to fillthe grooves) is dipped in a metal-polishing liquid and the liquid isstirred at room temperature (25° C.) at 100 rpm. The difference in thethickness of the metal film, before and after the treatment, is obtainedin terms of the electric resistance value of the metal film, and theetching rate is derived from the thickness difference.

The polishing method using the metal-polishing liquid of the inventioncomprises applying the metal-polishing liquid of the invention to apolishing pad set on a platen, while keeping the surface of an articleto be polished in contact with the polishing pad, moving the polishingpad and the surface of the article relatively to each other to therebypolish the surface of the article.

Any ordinary polishing device is usable in the method of the invention.One example of the polishing device usable herein comprises a holder fora semiconductor substrate or the like having a surface to be polished,and a platen with a polishing pad stuck thereon (this is equipped with arevolution-variable motor or the like). The polishing pad is notspecifically defined, and any of nonwoven fabrics, polyurethane foams,porous fluorine resins and the like is usable.

The polishing condition is not also specifically defined. Preferably,however, the rotation speed of the platen is not so high, at most 200rpm, so that the substrate being polished is not off the polishing pad.The pressure under which the article (semiconductor substrate, etc.) tobe polished (having a film to be polished) is to be pressed against thepolishing pad preferably falls between 9.8 KPa and 98.1 KPa (between 100and 1000 gf/cm²), more preferably between 9.8 KPa and 49.0 KPa (between100 and 500 gf/cm²) for satisfying both the wafer in-plane uniformity ofthe polishing rate and the pattern planarization.

While polishing, a metal-polishing liquid is continuously fed to thepolishing pad via a pump or the like. The amount of the polishing liquidto be fed thereto is not specifically defined, but is preferably suchthat the surface of the polishing pad is all the time covered with thepolishing liquid.

After the completion of polishing, it is desirable that thesemiconductor substrate is well washed with running water, then thewater drops still remaining on the semiconductor substrate are removedby the use of a spin drier or the like, and thereafter the semiconductorsubstrate is dried.

In the polishing method of the invention, the metal-polishing liquid ofthe invention may be previously prepared and put in a tank (polishingliquid tank) in a polishing apparatus, or the metal-polishing liquid maybe prepared in the tank, and the liquid may be fed to a polishing pad;or the metal-polishing liquid material of the invention and a diluentmay be separately fed to a polishing apparatus, and mixed in theapparatus (including the pipe line therein). In the latter case, thepolishing liquid is prepared in the polishing apparatus while fed to apolishing pad. In any case, the above-mentioned method of producing themetal-polishing liquid of the invention applies to the preparation ofthe metal-polishing liquid.

For the method of preparing the metal-polishing liquid from its materialin a polishing apparatus, for example, employed is a method that a pipeline for the metal-polishing liquid material and a pipe line for adiluent meet to form one pipe line in which the two liquids from the twopipe lines are mixed and a diluted, metal-polishing liquid. Thepolishing liquid thus prepared is fed to a polishing pad.

For mixing, employable is any ordinary method, For example, the liquidsto be mixed are introduced under pressure into a narrow pipe line sothat they collide with each other to be mixed; or the pipe line for theliquids to be mixed therein is filled with a filler such as glass tubesor the like so that the liquid flows therein are repeatedly divided,separated and merged; or some power-driven blades are disposed in a pipeline.

For preparing the metal-polishing liquid in a pipe line, also employableis a method that a pipe line for the material for the metal-polishingliquid and a pipe line for a diluent are independently provided, and thepredetermined amount of the resultant two liquids from the twoindependent pipe lines are separately fed to a polishing pad on whichthey are mixed owing to the relative motion of the polishing pad to thesurface of the article to be polished.

In a case where the metal-polishing liquid material is composed of aplurality of constituent elements, different pipe lines may be providedfor every constituent element to prepare the metal-polishing liquid inthe same manner as the above-mentioned methods.

In the polishing method of the invention, the constituent elementcontaining an oxidizing agent of the metal-polishing liquid material maybe kept at a temperature not higher than 40° C. while the otherconstituent elements are kept at a temperature falling between roomtemperature and 100° C., and, after all these constituent elements havebeen mixed together, the resulting mixture may be kept at a temperaturenot higher than 40° C. Accordingly, the method is favorable forincreasing the solubility of poorly-soluble constituent elements of themetal-polishing liquid of the invention, since the solubility of theingredients increases at higher temperatures.

The constituent elements prepared by dissolving the ingredients (exceptthe oxidizing agent) at elevated temperatures falling between roomtemperature and 100° C. will deposit in their solutions when thetemperature of the solutions is lowered. Therefore, when cooledconstituent elements are used, they must previously be warmed in orderto dissolve the deposit therein. To deal with this problem, a means forsending a liquid containing a warmed and dissolved constituent element(mixture solution) through a pipe line and a means for sending adeposit-containing liquid under stirring through a pipe line and forwarming the pipe line to dissolve the deposit therein may be provided.

When warmed constituent elements are mixed and if the temperature of theconstituent element that contains an oxidizing agent is higher than 40°C., the oxidizing agent will decompose. Therefore, it is desirable thatthe temperature of the constituent element to be warmed, the temperatureof the oxidizing agent-containing constituent element to be cooled, andthe blend ratio of the two elements are so determined that thetemperature of the mixture prepared by mixing the two elements is nothigher than 40° C.

BEST MODES OF CARRYING OUT THE INVENTION

The invention is described concretely with reference to the followingExamples, which, however, are not intended to restrict the scope of theinvention. The polishing condition and others employed in the Examplesare mentioned below.

<<Polishing Condition>>

With a metal-polishing liquid being fed to a polishing pad fitted to aplaten in a polishing apparatus, via a metering pump, both the polishingpad and a substrate to be polished are rotated relatively to each other,and the substrate is polished with the polishing pad under the conditionmentioned below. Unless otherwise specifically indicated, the polishingliquid is previously prepared and stored in one tank (polishing liquidtank), and this is introduced into the metering pump.

Substrate: silicone substrate coated with a 1 μm-thick copper film.

Polishing pad: IC1000 (trade name by Rodel).

Polishing pressure: 20.6 KPa (210 g/cm²).

Relative speed of substrate to platen: 36 nm/min.

<<Matters Tested of Polished Samples>>

CMP rate: Before and after CMP, the difference in the copper filmthickness is obtained in terms of the electric resistance value of thefilm.

Etching rate: Before and after dipped in a metal-polishing liquidstirred at 25° C. at 100 rpm, the difference in the copper filmthickness is obtained in terms of the electric resistance value of thefilm.

In order to evaluate the actual CMP characteristics, grooves having adepth of 0.5 μm are formed in an insulating layer, a copper film isformed according to a known sputtering process, and this is buriedthrough known heat treatment. By the use of this silicon substrate withthe buried copper layer thereon, CMP is carried out. This is forevaluating the actual CMP characteristics of the substrate. After CMP,the substrate is checked with the naked eye and microscopically with anoptical microscope and an electronic microscope for the presence orabsence of erosion and scratches.

<<Change with Time>>

Immediately after its preparation, a metal-polishing liquid material isformulated into a metal-polishing liquid. On the other hand, 20 daysafter its preparation, the same metal-polishing liquid material isformulated into a metal-polishing liquid. The two metal-polishingliquids are subjected to the CMP under the above-mentioned condition,and the CMP rate and the etching rate are measured to check on whetherthere is a difference in data of the two cases.

EXAMPLE 1

(1) Preparation of Metal-Polishing Liquid Material:

First, 1.5 parts by weight of DL-malic acid (special-grade chemical)serving as an oxidized-metal etchant was dissolved in 61.5 parts byweight of water added thereto, to prepare a solution A. Next, 2 parts byweight of benzotriazole serving as a protective film-forming agent wasdissolved in 5 parts by weight of ethanol serving as a good solvent forthe protective film-forming agent to prepare a solution B. Finally, thesolution B was added to and mixed with the solution A to prepare ametal-polishing liquid material. This is a 10-fold concentrate of ametal-polishing liquid.

When stored at 0° C., the concentrate did not form a deposit therein.

(2) Preparation of Metal-Polishing Liquid:

To 7 parts by weight of the 10-fold concentrate, added was 33.2 parts byweight of aqueous hydrogen peroxide (special-grade chemical, aqueous 30%solution) serving as an oxidizing agent. Then, this was diluted with 63parts by weight of water serving as a diluent to prepare ametal-polishing liquid.

(3) CMP Test:

The resultant metal-polishing liquid was subjected to CMP under theabove-mentioned polishing condition. The CMP rate was 129 mm/min and theetching rate was 0.5 nm/min, and these were both good. And, nodifferences in the CMP rate and also in the etching rate due to changeof the metal-polishing liquid material caused by the passage of timewere found. Further, neither erosion nor scratches were found.

EXAMPLE 2

(1) Preparation of Metal-Polishing Liquid Material:

First, 1.5 parts by weight of DL-malic acid (special-grade chemical) wasdissolved in 61 parts by weight of water added thereto, to prepare asolution A. Next, 2 parts by weight of benzotriazole and 0.5 part byweight of ammonium polyacrylate, both serving as a protectivefilm-forming agent, were dissolved in 5 parts by weight of methanolserving as a good solvent for the protective film-forming agent toprepare a solution B. Finally, the solution B was added to the solutionA to prepare a metal-polishing liquid material. This is a 10-foldconcentrate of a metal-polishing liquid.

(2) Preparation of Metal-Polishing Liquid:

7 parts by weight of the 10-fold concentrate for the metal-polishingliquid was diluted with 63 parts by weight of water serving as adiluent, thereafter, 33.2 parts by weight of aqueous hydrogen peroxide(special-grade chemical, aqueous 30% solution) serving as an oxidizingagent was added thereto, to prepare a metal-polishing liquid.

(3) CMP Test:

The resultant metal-polishing liquid was used to carry out CMP under thesame condition as in Example 1. The CMP rate was 179 nm/min and theetching rate was 0.5 nm/min, and these were both good. And, nodifferences in the CMP rate and also in the etching rate due to changeof the metal-polishing liquid material caused by the passage of timewere found. Further, neither erosion nor scratches were found.

EXAMPLE 3

(1) Preparation of Metal-Polishing Liquid Material:

1.5 parts by weight of DL-malic acid (special-grade chemical) and 0.3part by weight of polyvinyl alcohol serving as a protective film-formingagent were dissolved in 58.7 parts by weight of water added thereto, toprepare a solution A. Next, 2.5 parts by weight of tolyltriazole servingas a protective film-forming agent was dissolved in 7 parts by weight ofacetone to prepare a solution B. Finally, the solution B was added tothe solution A to prepare a metal-polishing liquid material. This is a10-fold concentrate of a metal-polishing liquid.

(2) Preparation of Metal-Polishing Liquid:

7 parts by weight of the resultant 10-fold concentrate for themetal-polishing liquid was diluted with 63 parts by weight of waterserving as a diluent, thereafter, 33.2 parts by weight of aqueoushydrogen peroxide (special-grade chemical, aqueous 30% solution) servingas an oxidizing agent was further added thereto, to prepare ametal-polishing liquid.

(3) CMP Test:

The resultant metal-polishing liquid was used to carry out CMP under thesame condition as in Example 1. The CMP rate was 170 nm/min and theetching rate was 0.4 nm/min, and these were both good. And, nodifferences in the CMP rate and also in the etching rate due to changeof the metal-polishing liquid material caused by the passage of timewere found. Further, neither erosion nor scratches were found.

EXAMPLE 4

(1) Preparation of Metal-Polishing Liquid Material:

0.06 part by weight of naphthotriazole serving as a protectivefilm-forming agent was dissolved in 0.6 part by weight of methyl ethylketone, a good solvent for the protective film-forming agent, to preparea solution A. 10 parts by weight of potassium periodate serving as anoxidizing agent was dissolved in 20 parts by weight of water to preparea solution B. Next, the solution B was added to the solution A toprepare a solution C (this is a first constituent element).

On the other hand, 0.05 part by weight of DL-tartaric acid(special-grade chemical) serving as an oxidized-metal etchant wasdissolved in 30 parts by weight of water added thereto to prepare asolution D. 0.01 part by weight of naphthotriazole was dissolved in 0.1part by weight of methyl ethyl ketone to prepare a solution E. Then, thesolution B was added to the solution D to prepare a solution F (this isa second constituent element).

Subsequently, 0.1 part by weight of DL-tartaric acid was dissolved in 40parts by weight of water added thereto to prepare a diluent solution G(this is an aqueous solution serving as a diluent).

The solutions C, F and G thus prepared in the manner as above are thematerials to be formulated into a metal-polishing liquid.

(2) Preparation of Metal-Polishing Liquid:

The solutions C, F and G prepared in the above were mixed in a ratio byweight of 3/3/4 to prepare a metal-polishing liquid.

(3) CMP Test:

The resultant metal-polishing liquid was used to carry out CMP under thesame condition as in Example 1, The CMP rate was 126 nm/min and theetching rate was 0.4 nm/min, and these were both good. And, nodifferences in the CMP rate and also in the etching rate due to changeof the metal-polishing liquid material caused by the passage of timewere found. Further, neither erosion nor scratches were found.

EXAMPLE 5

(1) Preparation of Metal-Polishing Liquid Material:

To 0.15 part by weight of DL-malic acid (special-grade chemical), addedwere 0.4 part by weight of polyacrylamide serving as a protectivefilm-forming agent and 50 parts by weight of water, and these weredissolved to prepare a solution A. Next, 0.2 part by weight ofbenzotriazole was dissolved in 0.7 part by weight of ethylene glycol toprepare a solution B. Finally, to the solution A under heat at 45° C.,the solution B was added to it kept at 45° C. to prepare a solution C,which is a material for a metal-polishing liquid. The solution C waskept also at 45° C.

(2) Preparation of Metal-Polishing Liquid:

Kept at 45° C., the solution C was diluted with 20 parts by weight ofwater heated at 45° C., and then 33.2 parts by weight of aqueoushydrogen peroxide (special-grade chemical, aqueous 30% solution) at 20°C. was poured thereinto to prepare a metal-polishing liquid. Thetemperature of the thus-prepared, metal-polishing liquid was 36° C.

(3) CMP Test:

The above-mentioned metal-polishing liquid was used to carry out CMPunder the same condition as in Example 1. The CMP rate was 167 nm/minand the etching rate was 0.3 nm/min, and these were both good. And, nodifferences in the CMP rate and also in the etching rate due to changeof the metal-polishing liquid material caused by the passage of timewere found. Further, neither erosion nor scratches were found.

EXAMPLE 6

(1) Preparation of Metal-Polishing Liquid Material:

A metal-polishing liquid material was prepared in the same manner as inExample 1. In this, however, benzotriazole was previously ground in amortar with a pestle for 5 minutes, before it was dissolved. After thusground, the benzotriazole powder was observed with an opticalmicroscope, and its mean particle size was 80 μm. In this Example, bythe use of the benzotriazole having a reduced particle size through thispre-treatment, the time taken to completely dissolve benzotriazole inethanol was shortened from 5 minutes to 2 minutes.

(2) Preparation of Metal-Polishing Liquid, and CMP Test:

By the use of the metal-polishing liquid material prepared in the above,a metal-polishing liquid was formulated in the same manner as inExample 1. This was used to carry out CMP under the same condition as inExample 1, As a result, the CMP rate was 130 nm/min and the etching ratewas 0.5 nm/min, and these were both good. And, no differences in the CMPrate and also in the etching rate due to change of the metal-polishingliquid material caused by the passage of time were found. Further,neither erosion nor scratches were found.

EXAMPLE 7

To the metal-polishing liquid of Example 2, added was 1 part by weightof colloidal silica having a mean particle size of 100 nm and serving asabrasive grains, and this was dispersed therein to prepare anothermetal-polishing liquid, The metal-polishing liquid thus prepared hereinwas used to carry out CMP under the same condition as in Example 1. TheCMP rate was 252 nm/min and the etching rate was 0.6 nm/min, and thesewere both good. And, no differences in the CMP rate and also in theetching rate due to change of the metal-polishing liquid material causedby the passage of time were found. Further, neither erosion norscratches were found.

EXAMPLE 8

A metal-polishing liquid was prepared in the same manner as in Example2. In this, however, the solution B and 10 parts by weight of colloidalsilica having a mean particle size of 48 nm were added to the solution Ato prepare a material for the polishing liquid.

The metal-polishing liquid thus prepared herein was used to carry outCMP under the same condition as in Example 1. The CMP rate was 250nm/min and the etching rate was 0.5 nm/min, and these were both good.And, no differences in the CMP rate and also in the etching rate due tochange of the metal-polishing liquid material caused by the passage oftime were found. Further, neither erosion nor scratches were found.

EXAMPLE 9

The metal-polishing liquid of Example 1 was used to carry out CMP underthe same condition as in Example 1. In this, however, themetal-polishing liquid was prepared by mixing the ingredients in thepipe line. Concretely, a diluted liquid prepared by diluting 7 parts byweight of the 10-fold concentrate for the metal-polishing liquid with 63parts by weight of water added thereto, and aqueous hydrogen peroxide(special-grade chemical, aqueous 30% solution) were put into differenttanks, and these were separately fed into different pipe lines viadifferent metering pumps, and mixed at the junction of the two pipelines, in a flow rate ratio (by volume) of diluted liquid/aqueoushydrogen peroxide of 7/3. With that, the resulting mixture wasintroduced into a pipe line filled with a large number of glass tubes of3 mm in length, and then fed to the polishing pad in the apparatus, tocarry out the polishing.

As a result, the CMP rate was 129 nm/min and the etching rate was 0.5nm/min, and these were both good. And, no differences in the CMP rateand also in the etching rate due to change of the metal-polishing liquidmaterial caused by the passage of time were found. Further, neithererosion nor scratches were found.

EXAMPLE 10

The metal-polishing liquid of Example 4 was used to carry out CMP underthe same condition as in Example 1. In this, however, the polishingliquid was prepared by mixing the ingredients in the pipe line.Concretely, the solution C and a mixture of the solutions F and G wereput into different tanks, and these were separately fed into differentpipe lines via different metering pumps, and mixed at the junction ofthe two pipe lines, in a flow rate ratio (by volume) of solutionC/(solution F+solution G) of 3/7. The resulting mixture was fed to thepolishing pad in the apparatus.

As a result, the CMP rate was 125 nm/min and the etching rate was 0.4nm/min, and these were both good. And, no differences in the CMP rateand also in the etching rate due to change of the metal-polishing liquidmaterial caused by the passage of time were found. Further, neithererosion nor scratches were found.

EXAMPLE 11

A metal-polishing liquid was prepared in the same manner as in Example1, except that the amount of ethanol used in preparing the 10-foldconcentrate for the metal-polishing liquid in Example 1 was increasedfrom 5 parts by weight to 50 parts by weight. This was used to carry outCMP, and the etching rate was 0.5 nm/min and the CMP rate was 62 nm/min.

EXAMPLE 12

(1) Preparation of Metal-Polishing Liquid Material:

First, 66 parts by weight of water was added to 2 parts by weight ofbenzotriazole serving as a protective film-forming agent, and 0.4 partby weight of polyoxyethylene(10) glycol serving as a surfactant wasadded thereto. These were stirred with a stirring blades in a warm waterbath at 40° C., and dissolved, 1.5 parts by weight of DL-malic acid(special-grade chemical) serving as an oxidized-metal etchant was addedto and dissolved in the resulting solution to prepare a 10-foldconcentrate of a metal-polishing liquid which corresponds to thematerial for the metal-polishing liquid.

When stored at 0° C., the concentrate did not form a deposit therein.

(2) Preparation of Metal-Polishing Liquid:

7 parts by weight of the 10-fold concentrate for the metal-polishingliquid was diluted with 63 parts by weight of water serving as adiluent, to which was added 33.2 parts by weight of aqueous hydrogenperoxide (special-grade chemical, aqueous 30% solution) serving as anoxidizing agent to prepare a metal-polishing liquid.

(3) CMP Test:

The resultant metal-polishing liquid was used to carryo out CMP underthe same condition as in Example 1. The CMP rate was 187 nm/min and theetching rate was 0.7 nm/min, and these were both good. And, nodifferences in the CMP rate and also in the etching rate due to changeof the metal-polishing liquid material caused by the passage of timewere found. Further, neither erosion nor scratches were found.

EXAMPLE 13

66 parts by weight of water was added to 2 parts by weight oftolyltriazole serving as a protective film-forming agent, and then 0.4part by weight of polyoxyethylene(9) octylphenyl ether also serving as aprotective film-forming agent was added thereto, These were stirred witha stirring blades in a warm water bath at 40° C., and dissolved. 1.5parts by weight of DL-tartaric acid (special-grade chemical) was addedto and dissolved in the resulting solution to prepare a 10-foldconcentrate of a metal-polishing liquid which corresponds to thematerial for the metal-polishing liquid.

(2) Preparation of Metal-Polishing Liquid:

7 parts by weight of the resultant 10-fold concentrate for themetal-polishing liquid was diluted with 63 parts by weight of water, towhich was added 33.2 parts by weight of aqueous hydrogen peroxide(special-grade chemical, aqueous 30% solution) to prepare ametal-polishing liquid.

(3) CMP Test:

The metal-polishing liquid was used to carry out CMP under the samecondition as in Example 1. The CMP rate was 186 nm/min and the etchingrate was 0.3 nm/min, and these were both good. And, no differences inthe CMP rate and also in the etching rate due to change of themetal-polishing liquid material caused by the passage of time werefound. Further, neither erosion nor scratches were found.

EXAMPLE 14

(1) Preparation of Metal-Polishing Liquid Material:

0.05 part by weight of benzotriazole serving as a protectivefilm-forming agent, 0.1 part by weight of ammonium butylsulfate servingas a surfactant, and 10 parts by weight of potassium periodate servingas an oxidizing agent were added to 20 parts by weight of water. Thesewere stirred with stirring blades in a warm water bath at 40° C. anddissolved to prepare a solution A.

Next, 0.05 part by weight of DL-tartaric acid (special-grade chemical)serving as an oxidized-metal etchant was dissolved in 30 parts by weightof water added thereto, and 0.15 part by weight of a benzotriazoleserving as a protective film-forming agent and 0.1 parts by weight ofammonium butylsulfate serving as a surfactant were added thereto. Thesewere stirred with stirring blades in a warm water bath at 40° C. anddissolved to prepare a solution B.

In the manner as above, prepared were the solutions A and B for thematerial for a metal-polishing liquid. On the other hand, 0.1 part byweight of DL-tartaric acid was dissolved in 40 parts by weight of wateradded thereto, to prepare an aqueous diluent solution.

(2) Preparation of Metal-Polishing Liquid:

The solutions A, B and the aqueous diluent solution prepared in theabove were mixed in a ratio by weight of 3/3/4 to prepare ametal-polishing liquid.

(3) CMP Test:

The metal-polishing liquid was used to carry out CMP under the samecondition as in Example 1. The CMP rate was 126 nm/min and the etchingrate was 0.4 nm/min, and these were both good. And, no differences inthe CMP rate and also in the etching rate due to change of themetal-polishing liquid material caused by the passage of time werefound. Further, neither erosion nor scratches were found.

EXAMPLE 15

(1) Preparation of Metal-Polishing Liquid Material:

0.15 part by weight of DL-malic acid (special-grade chemical) wasdissolved in 50 parts by weight of water added thereto. With theresulting solution being kept at 45° C., 0.2 part by weight ofbenzotriazole and 0.7 part by weight of a surfactant, succinamide wereadded thereto and dissolved therein, to prepare a solution A.

(2) Preparation of Metal-Polishing Liquid:

Kept at 45° C., the solution A was diluted with 20 parts by weight ofwater heated at 45° C., and then 33.2 parts by weight of aqueoushydrogen peroxide (special-grade chemical, aqueous 30% solution) at 20°C. was poured thereinto to prepare a metal-polishing liquid. Thetemperature of the thus-prepared, metal-polishing liquid was 36° C.

(3) CMP Test:

The metal-polishing liquid was used to carry out CMP under the samecondition as in Example 1. The CMP rate was 127 nm/min and the etchingrate was 0.3 nm/min, and these were both good. And, no differences inthe CMP rate and also in the etching rate due to change of themetal-polishing liquid material caused by the passage of time werefound. Further, neither erosion nor scratches were found.

EXAMPLE 16

(1) Preparation of Metal-Polishing Liquid Material:

A metal-polishing liquid material was prepared in the same manner as inExample 12. In this, however, benzotriazole to be used was pre-treatedin the same manner as in Example 6 to have a mean particle size of 80μn. By the pre-treatment, in this, the time for complete benzotriazoledissolution was shortened from 15 minutes to 5 minutes.

(2) Preparation of Metal-Polishing Liquid, and CMP Test:

By the use of the material prepared in the above, a metal-polishingliquid was formulated in the same manner as in Example 12. This was usedto carry out CMP under the same condition as in Example 1. As a result,the CMP rate was 185 nm/min and the etching rate was 0.6 nm/min, andthese were both good. And, no differences in the CMP rate and also inthe etching rate due to change of the metal-polishing liquid materialcaused by the passage of time were found. Further, neither erosion norscratches were found.

EXAMPLE 17

To the metal-polishing liquid of Example 12, further added was 1 part byweight of colloidal silica having a mean particle size of 100 nm andserving as abrasive grains, and this was dispersed in the liquid toprepare another metal-polishing liquid. The metal-polishing liquid thusprepared herein was used to carry out CMP under the same condition as inExample 1. The CMP rate was 250 nm/min and the etching rate was 0.6nm/min, and these were both good, And, no differences in the CMP rateand also in the etching rate due to change of the metal-polishing liquidmaterial caused by the passage of time were found. Further, neithererosion nor scratches were found.

EXAMPLE 18

A metal-polishing liquid was prepared in the same manner as in Example12. In this, however, 10 parts by weight of colloidal silica having amean particle size of 48 nm was further added to the 10-fold concentratefor the metal-polishing liquid prepared in Example 12, to prepareanother metal-polishing liquid.

The metal-polishing liquid thus prepared herein was used to carry outCMP under the same condition as in Example 1. The CMP rate was 244nm/min and the etching rate was 0.6 nm/min, and these were both good.And, no differences in the CMP rate and also in the etching rate due tochange of the metal-polishing liquid material caused by the passage oftime were found. Further, neither erosion nor scratches were found.

EXAMPLE 19

The metal-polishing liquid of Example 12 was used to carry out CMP underthe same condition as in Example 1. In this, however, themetal-polishing liquid was prepared by mixing the ingredients in thepipe line. Concretely, a diluted liquid prepared by diluting 7 parts byweight of the 10-fold concentrate for the metal-polishing liquid with 63parts by weight of water added thereto, and 33.2 parts by weight ofaqueous hydrogen peroxide (special-grade chemical, aqueous 30% solution)were put into different tanks, and these were separately fed intodifferent pipe lines via different metering pumps, and mixed at thejunction of the two pipe lines, in a flow rate ratio (by volume) of thediluted liquid/aqueous hydrogen peroxide of 7/3. With that, theresulting mixture was introduced into a pipe line filled with a largenumber of glass tubes of 3 mm in length, and then fed to the polishingpad in the apparatus.

As a result, the CMP rate was 177 nm/min and the etching rate was 0.5nm/min, and these were both good. And, no differences in the CMP rateand also in the etching rate due to change of the metal-polishing liquidmaterial caused by the passage of time were found. Further, neithererosion nor scratches were found.

EXAMPLE 20

The metal-polishing liquid of Example 14 was used to carry out CMP underthe same condition as in Example 1. In this, however, themetal-polishing liquid was prepared by mixing the ingredients in thepipe line. Concretely, the solution A, and a mixture of the solution Band the aqueous diluent solution were put into different tanks, andthese were separately fed into different pipe lines via differentmetering pumps, and mixed at the junction of the two pipe lines, in aflow rate ratio (by volume) of solution A/(solution B+aqueous diluentsolution) of 3/7. The resulting mixture was fed to the polishing pad inthe apparatus.

As a result, the CMP rate was 124 nm/min and the etching rate was 0.4nm/min, and these were both good. And, no differences in the CMP rateand also in the etching rate due to change of the metal-polishing liquidmaterial caused by the passage of time were found. Further, neithererosion nor scratches were found.

COMPARATIVE EXAMPLE 1

A 10-fold concentrate for a metal-polishing liquid was prepared in thesame manner as in Example 1, except that ethanol was not added thereto.When this was stored in a refrigerator at 5° C., it formed a solidprecipitate therein. It could not be directly formulated into ametal-polishing liquid and therefore could not be evaluated.

COMPARATIVE EXAMPLE 2

A 10-fold concentrate for a metal-polishing liquid was prepared in thesame manner as in Example 12, except that polyoxyethylene(10) glycol wasnot added thereto, When this was stored in a refrigerator at 5° C., itformed a solid precipitate therein, It could not be directly formulatedinto a metal-polishing liquid and therefore could not be evaluated.

INDUSTRIAL APPLICABILITY

The invention provides a metal-polishing liquid material of highconcentration. For transport, storage and the like, thehigh-concentration material can be used, and, when carrying out theactual polishing, a polishing liquid can be readily prepared by adding adiluent or the like to the material. Accordingly, the invention canreduce the production costs of metal-polishing liquids, and reduce thenumber of tanks necessary for storing and transporting metal-polishingliquids. In addition, the invention can reduce the space for storage ofmetal-polishing liquids, and reduce the scale of polishing devices andthe volume of polishing liquid tanks and the like. According to theinvention, buried metal layer patterns of high reliability can beformed. Accordingly, the invention is especially useful for fabricationand the like of semiconductor devices.

1. A metal-polishing liquid material comprising an ingredient group ofan oxidized-metal etchant, a protective film-forming agent and at leastone of esters, ethers, polysaccharides, salts of amino acids,polycarboxylic acids, salts of polycarboxylic acids, vinyl polymers,sulfonic acids, sulfonates, and amides.
 2. The metal-polishing liquidmaterial according to claim 1, further comprising at least one of anoxidizing agent and water.
 3. The metal-polishing liquid materialaccording to claim 1, comprising the ingredient group of themetal-polishing liquid in a divided state of at least two constituentelements not mixed.
 4. The metal-polishing liquid material according toclaim 1, wherein at least a part of the protective film-forming agent issolid having a mean particle size of at most 100 μm.
 5. Themetal-polishing liquid material according to claim 1, further comprisingabrasive grains.
 6. A metal-polishing liquid which comprises anoxidizing agent, an oxidized-metal etchant, a protective film-formingagent, at least one of esters, ethers, polysaccharides, salts of aminoacids, polycarboxylic acids, salts of polycarboxylic acids, vinylpolymers, sulfonic acids, sulfonates, and amides, and water.
 7. Themetal-polishing liquid according to claim 6, wherein at least a part ofthe protective film-forming agent is solid, having a mean particle sizeof at most 100 μm.
 8. The metal-polishing liquid according to claim 6,further comprising abrasive grains.
 9. A method for producing ametal-polishing liquid, comprising a step of diluting themetal-polishing liquid material of claim 1 with a diluent.
 10. A methodfor producing a metal-polishing liquid of claim 6, comprising a step ofdiluting a metal-polishing liquid material comprising at least oneingredient of the ingredient group of the metal-polishing liquid with anaqueous solution for dilution of at least one ingredient of theingredient group.
 11. A method for producing a metal-polishing liquid ofclaim 6, which comprises a step of mixing the following in any desiredorder: a first constituent element that contains at least one ingredientof the ingredient group of the metal-polishing liquid, a secondconstituent element that contains at least one of the other ingredientsof the ingredient group, and a diluent.
 12. The method for producing ametal-polishing liquid according to claim 11, wherein the diluent iswater or an aqueous diluent solution.
 13. The method for producing ametal-polishing liquid according to claim 11, wherein the firstconstituent element comprises an oxidizing agent, and the secondconstituent element comprises an oxidized-metal etchant, a protectivefilm-forming agent, and any one selected from the following (1)-(4): (1)at least one of esters, ethers, polysaccharides, salts of amino acids,polycarboxylic acids, salts of polycarboxylic acids, vinyl polymers,sulfonic acids, sulfonates, and amides, (2) a solvent in which thesolubility of the protective film-forming agent is at least 25 g/liter,(3) a good solvent of the solubility of the protective film-formingagent, and (4) at least one of alcohols, ethers and ketones.
 14. Themethod for producing a metal-polishing liquid according to claim 11,wherein the first constituent element further comprises at least oneselected from the following (1)-(5): (1) the protective film-formingagent and the dissolution promoter, (2) the protective film-formingagent and at least one of esters, ethers, polysaccharides, salts ofamino acids, polycarboxylic acids, salts of polycarboxylic acids, vinylpolymers, sulfonic acids, sulfonates, and amides, (3) the protectivefilm-forming agent and the solvent in which the solubility of theprotective film-forming agent is at least 25 g/liter, (4) the protectfilm-forming agent and the good solvent for the protective film-formingagent, and (5) the protective film-forming agent and at least one ofalcohols, ethers and ketones.
 15. The method for producing ametal-polishing liquid as claimed in claim 11, wherein in the mixingstep, the oxidizing agent and the oxidizing agent-containing mixture arekept at a temperature of at most 40° C.
 16. The method for producing ametal-polishing liquid as claimed in claim 11, wherein at least a partof the protective film-forming agent is solid, having a mean particlesize of at most 100 μm, and is dissolved or dispersed in themetal-polishing liquid in the mixing step.
 17. A polishing methodcomprising a polishing step of: applying the metal-polishing liquid ofclaim 6 to a polishing pad set on a platen, and polishing the surface ofan article to be polished with the polishing pad by moving the polishingpad and the surface of the article relatively to each other whilekeeping the surface of the article in contact with the polishing pad.18. The polishing method according to claim 17, further comprising astep of mixing the constituent elements of the metal-polishing liquid toprepare the metal-polishing liquid, prior to the polishing step, whereinthe mixing step is for mixing the following: a first constituent elementthat contains at least one ingredient of the ingredient group, a secondconstituent element that contains at least one of the other ingredientsof the ingredient group, and a diluent, in any desired order.
 19. Amethod for producing a metal-polishing liquid, comprising a step ofdiluting the metal-polishing liquid material of claim 5 with a diluent.20. The method for producing a metal-polishing liquid according to claim9, wherein the diluent is water or an aqueous diluent solution.
 21. Themetal-polishing liquid material according to claim 3, wherein eachingredient of said ingredient group is a different ingredient.
 22. Themetal-polishing liquid material according to claim 2, wherein theprotective film-forming agent, the dissolution promoter, theoxidized-metal etchant, the oxidizing agent and water are differentingredients.
 23. The metal-polishing liquid material according to claim1, wherein the protective film-forming agent is at least one selectedfrom the group consisting of ammonia, amines, amino acids, imines,azoles, mercaptans, polysaccharides, salts of amino acids,polycarboxylic acids and their salts, and vinyl polymers.
 24. Themetal-polishing liquid according to claim 6, wherein the protectivefilm-forming agent is at least one selected from the group consisting ofammonia, amines, amino acids, imines, azoles, mercaptans,polysaccharides, salts of amino acids, polycarboxylic acids and theirsalts, and vinyl polymers.
 25. A metal-polishing liquid materialcomprising an ingredient group of an oxidized-metal etchant, aprotective film-forming agent, and a solvent in which the solubility ofthe protective film-forming agent is at least 25 g/liter.
 26. Ametal-polishing liquid material comprising an ingredient group of anoxidized-metal etchant, a protective film-forming agent, and a goodsolvent for the protective film-forming agent.
 27. A metal-polishingliquid material comprising an ingredient group of an oxidized-metaletchant, a protective film-forming agent, and at least one of alcohols,ethers and ketones.
 28. A metal-polishing liquid material comprising aningredient group of an oxidized-metal etchant, a protective film-formingagent, and a dissolution promoter for the protective film-forming agent,wherein a polishing liquid is prepared by diluting the metal-polishingliquid material with at least 10-fold dilution factor of themetal-polishing liquid material.
 29. The metal-polishing liquid materialaccording to claim 25, further comprising at least one of an oxidizingagent and water.
 30. The metal-polishing liquid material according toclaim 26, further comprising at least one of an oxidizing agent andwater.
 31. The metal-polishing liquid material according to claim 27,further comprising at least one of an oxidizing agent and water.
 32. Themetal-polishing liquid material according to claim 28, furthercomprising at least one of an oxidizing agent and water.
 33. Themetal-polishing liquid material according to claim 25, comprising theingredient group of the metal-polishing liquid material in a dividedstate at least into two constituent elements not mixed.
 34. Themetal-polishing liquid material according to claim 26, comprising theingredient group of the metal-polishing liquid material in a dividedstate of at least two constituent elements not mixed.
 35. Themetal-polishing liquid material according to claim 27, comprising theingredient group of the metal-polishing liquid material in a dividedstate of at least two constituent elements not mixed.
 36. Themetal-polishing liquid material according to claim 28, comprising theingredient group of the metal-polishing liquid material in a dividedstate of at least two constituent elements not mixed.
 37. Themetal-polishing liquid material according to claim 28, wherein thedissolution promoter is a surfactant.
 38. The metal-polishing liquidmaterial according to claim 28, wherein the surfactant is at least oneof esters, ethers, polysaccharides, salts of amino acids, polycarboxylicacids, salts of polycarboxylic acids, vinyl polymers, sulfonic acids,sulfonates, and amides.
 39. The metal-polishing liquid materialaccording to claim 26, wherein the dissolution promoter is a solvent inwhich the solubility of the protective film-forming agent is at least 25g/liter.
 40. The metal-polishing liquid material according to claim 27,wherein the dissolution promoter is a solvent in which the solubility ofthe protective film-forming agent is at least 25 g/liter.
 41. Themetal-polishing liquid material according to claim 28, wherein thedissolution promoter is a solvent in which the solubility of theprotective film-forming agent is at least 25 g/liter.
 42. Themetal-polishing liquid material according to claim 25, wherein thesolvent is a good solvent for the protective film-forming agent.
 43. Themetal-polishing liquid material according to claim 27, wherein thesolvent is a good solvent for the protective film-forming agent.
 44. Themetal-polishing liquid material according to claim 28, wherein thesolvent is a good solvent for the protective film-forming agent.
 45. Themetal-polishing liquid material according to claim 25, wherein thesolvent is at least one of alcohols, ethers and ketones.
 46. Themetal-polishing liquid material according to claim 26, wherein thesolvent is at least one of alcohols, ethers and ketones.
 47. Themetal-polishing liquid material according to claim 28, wherein thesolvent is at least one of alcohols, ethers and ketones.
 48. Themetal-polishing liquid material according to claim 25, wherein theamount of the solvent is smaller than 50 g relative to 100 g of a totalamount of the material.
 49. The metal-polishing liquid materialaccording to claim 26, wherein the amount of the solvent is smaller than50 g relative to 100 g of a total amount of the material.
 50. Themetal-polishing liquid material according to claim 27, wherein theamount of the solvent is smaller than 50 g relative to 100 g of a totalamount of the material.
 51. The metal-polishing liquid materialaccording to claim 25, wherein at least a part of the protectivefilm-forming agent is solid having a mean particle size of at most 100μm.
 52. The metal-polishing liquid material according to claim 26,wherein at least a part of the protective film-forming agent is solidhaving a mean particle size of at most 100 μm.
 53. The metal-polishingliquid material according to claim 27, wherein at least a part of theprotective film-forming agent is solid having a mean particle size of atmost 100 μm.
 54. The metal-polishing liquid material according to claim28, wherein at least a part of the protective film-forming agent issolid having a mean particle size of at most 100 μm.
 55. Themetal-polishing liquid material according to claim 25, furthercomprising abrasive grains.
 56. The metal-polishing liquid materialaccording to claim 26, further comprising abrasive grains.
 57. Themetal-polishing liquid material according to claim 27, furthercomprising abrasive grains.
 58. The metal-polishing liquid materialaccording to claim 28, further comprising abrasive grains.
 59. Ametal-polishing liquid comprising an ingredient group of an oxidizingagent, an oxidized-metal etchant, a protective film-forming agent, asolvent and water, wherein the solubility of the protective film-formingagent in the solvent is at least 25 g/liter.
 60. A metal-polishingliquid comprising an ingredient group of an oxidizing agent, anoxidized-metal etchant, a protective film-forming agent, a good solventfor the protective film-forming agent and water.
 61. A metal-polishingliquid comprising an ingredient group of an oxidizing agent, anoxidized-metal etchant, a protective film-forming agent, at least one ofalcohols, ethers and ketones, and water.
 62. The metal-polishing liquidaccording to claim 60, wherein the dissolution promoter is a solvent inwhich the solubility of the protective film-forming agent is at least 25g/liter.
 63. The metal-polishing liquid according to claim 61, whereinthe dissolution promoter is a solvent in which the solubility of theprotective film-forming agent is at least 25 g/liter.
 64. Themetal-polishing liquid according to claim 59, wherein at least a part ofthe protective film-forming agent is solid, having a mean particle sizeof at most 100 μm.
 65. The metal-polishing liquid according to claim 60,wherein at least a part of the protective film-forming agent is solid,having a mean particle size of at most 100 μm.
 66. The metal-polishingliquid according to claim 61, wherein at least a part of the protectivefilm-forming agent is solid, having a mean particle size of at most 100μm.
 67. The metal-polishing liquid according to claim 59, furthercomprising abrasive grains.
 68. The metal-polishing liquid according toclaim 60, further comprising abrasive grains.
 69. The metal-polishingliquid according to claim 61, further comprising abrasive grains.
 70. Amethod for producing a metal-polishing liquid of claim 59, comprising astep of diluting a metal-polishing liquid material comprising at leastone ingredient of the ingredient group with an aqueous solution fordilution of at least one ingredient of the ingredient group.
 71. Amethod for producing a metal-polishing liquid of claim 60, comprising astep of diluting a metal-polishing liquid material comprising at leastone ingredient of the ingredient group with an aqueous solution fordilution of at least one ingredient of the ingredient group.
 72. Amethod for producing a metal-polishing liquid of claim 61, comprising astep of diluting a metal-polishing liquid material comprising at leastone ingredient of the ingredient group with an aqueous solution fordilution of at least one ingredient of the ingredient group.
 73. Amethod for producing a metal-polishing liquid of claim 59, whichcomprises a step of mixing the following in any desired order: a firstconstituent element that contains at least one ingredient of theingredient group of the metal-polishing liquid, a second constituentelement that contains at least one of the other ingredients of theingredient group, and a diluent.
 74. A method for producing ametal-polishing liquid of claim 60, which comprises a step of mixing thefollowing in any desired order: a first constituent element thatcontains at least one ingredient of the ingredient group of themetal-polishing liquid, a second constituent element that contains atleast one of the other ingredients of the ingredient group, and adiluent.
 75. A method for producing a metal-polishing liquid of claim61, which comprises a step of mixing the following in any desired order:a first constituent element that contains at least one ingredient of theingredient group, a second constituent element that contains at leastone of the other ingredients of the ingredient group, and a diluent. 76.A polishing method comprising a polishing step of: applying themetal-polishing liquid of claim 59 to a polishing pad set on a platen,and polishing the surface of an article to be polished with thepolishing pad by moving the polishing pad and the surface of the articlerelatively to each other while keeping the surface of the article incontact with the polishing pad.
 77. A polishing method comprising apolishing step of: applying the metal-polishing liquid of claim 60 to apolishing pad set on a platen, and polishing the surface of an articleto be polished with the polishing pad by moving the polishing pad andthe surface of the article relatively to each other while keeping thesurface of the article in contact with the polishing pad.
 78. Apolishing method comprising a polishing step of: applying themetal-polishing liquid of claim 61 to a polishing pad set on a platen,and polishing the surface of an article to be polished with thepolishing pad by moving the polishing pad and the surface of the articlerelatively to each other while keeping the surface of the article incontact with the polishing pad.
 79. The metal-polishing liquid materialaccording to claim 25, wherein the protective film-forming agent is atleast one selected from the group consisting of ammonia, amines, aminoacids, imines, azoles, mercaptans, polysaccharides, salts of aminoacids, polycarboxylic acids and their salts, and vinyl polymers.
 80. Themetal-polishing liquid material according to claim 26, wherein theprotective film-forming agent is at least one selected from the groupconsisting of ammonia, amines, amino acids, imines, azoles, mercaptans,polysaccharides, salts of amino acids, polycarboxylic acids and theirsalts, and vinyl polymers.
 81. The metal-polishing liquid materialaccording to claim 27, wherein the protective film-forming agent is atleast one selected from the group consisting of ammonia, amines, aminoacids, imines, azoles, mercaptans, polysaccharides, salts of aminoacids, polycarboxylic acids and their salts, and vinyl polymers.
 82. Themetal-polishing liquid material according to claim 28, wherein theprotective film-forming agent is at least one selected from the groupconsisting of ammonia, amines, amino acids, imines, azoles, mercaptans,polysaccharides, salts of amino acids, polycarboxylic acids and theirsalts, and vinyl polymers.
 83. The metal-polishing liquid according toclaim 59, wherein the protective film-forming agent is at least oneselected from the group consisting of ammonia, amines, amino acids,imines, azoles, mercaptans, polysaccharides, salts of amino acids,polycarboxylic acids and their salts, and vinyl polymers.
 84. Themetal-polishing liquid according to claim 60, wherein the protectivefilm-forming agent is at least one selected from the group consisting ofammonia, amines, amino acids, imines, azoles, mercaptans,polysaccharides, salts of amino acids, polycarboxylic acids and theirsalts, and vinyl polymers.
 85. The metal-polishing liquid according toclaim 61, wherein the protective film-forming agent is at least oneselected from the group consisting of ammonia, amines, amino acids,imines, azoles, mercaptans, polysaccharides, salts of amino acids,polycarboxylic acids and their salts, and vinyl polymers.